1.Description of the bug. What did you do before the bug appeared?
I load the website in a tab, then change to a different tab and move back. Everything on the S&F website will not react on me attempting to interact with it. I have seen the website react in the same way twice when I had a program auto-fullscreen, but I can't reproduce this variant. Going on a different tab does always result in S&F not reacting anymore though unless I reload the website.

2.When did the bug appear, meaning time and date?
I am having this issue since around christmas. I haven't written down since when exactly.

3.Can you reproduce the bug?
I have it every single day, every time I open the website. The moment I go on a different tab, I will no longer be able to do anything without reloading the website.

4.Have you made a screenshot (Print Screen)?
Interaction possible (notice that "Magic Shop" is highlighted)

Go to different tab

Return to S&F, interaction not possible (no highlight anywhere)

5.Browser details. Include the browser type and version (for example: Mozilla 5.2.8); The version of Adobe Flashplayer (click); System details; Internet connectivity and activity; and anything else you feel pertinent to the problem.
Mozilla Firefox 49.0.2
Adobe Flashplayer 24,0,0,194
Windows 8.1 64-bit
I played the game with three different kinds of internet since the bug happened: via LAN at my residential home, via WIFI in university and via WIFI in the Hostel I am now staying at. All with the same result.
I usually have at least one other tab open which is almost always Youtube. Occassionally, I also have open: Hotmail, Facebook, TV Tropes, random News Websites. The bug happens, no matter on which tab I go. It also happens if S&F is the only website and I simply open a new empty tab.

6.Your In-game name and the server on which the bug appeared.
I have it with both of my accounts, "Lynegin Yunidock" on Server 10 and Server 14.

(My apologies for the long silence, I happened to go backpacking for a month without internet)

Chrome does it just fine, so it seems to be a Firefox issue. I update Flash, I reinstalled it, nothing. I assume, that Firefox may just be doomed...?

And the menu was my way of showing where my mouse is so that it is clear that when I didn't move tabs, the buttons react while they don't when I switched. The menu in itself had no other reason ^^"
I have restarted my computer and the browser countless times (as said, that haunted me for weeks already). I am clearing my cashe regulary every two weeks as part of my CCleaner routine, so I assume that that's also not the part.

I mean, I can deal with the whole reloading, as annoying as it is. I just had hoped, there might be a simple reason that would fix the situation xD"